Yeah, I detailed the maps and scales from Franz Joseph, Starfleet Battles, Star Trek Maps, and FASA in the first post, and continued to compare and combine and analyze them throughout the thread. I haven’t tackled Star Charts because it falls far afield from everything else I’m interested in (60s-70s-80s), and made too many fundamental changes to where it just doesn’t seem worthwhile to try to make it mesh.
Well, all maps have their problems. ST Maps uses cardinal stars, but is very uneven on their placements (like Spica to Regulus, to Rigel and Cerberus) even with sizable changes to Hipparchus data since (like with Deneb) It also has the little known 60 degree tilt issue (of using Earth's horizontal plane instead of the galactic plane, as a cornerstone of it's coordinates) And has oddities like putting Deneva up 'high' maybe as a result.
So there is no fully perfect solution. And Gene Roddenberry likely threw out a lot of old TOS assumptions as TNG began, and developed. And the warp scale started to be solidified, too, with mention of 39 C figures and 1500, and 2300 plus and so on, implied in dialogue.
I feel Star Charts adapts fairly well, but was made largely due to DS9 presenting the 'core' Federation as quite small, and with only two hundred light years from DS9 and Station K-7 (from Ursa Major to about Eridanus somewhere, it seems, by implication) Early in TNG though, an 8,000 to 10,000 LY wide Federation did seem posited in behind the scenes references. Clearly ideas were evolving as the show developed - and franchise, too.
So - as I see it: the Federation is between 400 to 900 or so LY wide on AVERAGE, has about a thousand worlds in TOS (from minor outposts and mining colonies to full settlements) and got up to 7.3 times bigger by Nemesis.
Then occupies maybe 2250 sectors of 400 square and 8000 cubic light years (each with an average of 3.25 settled planets) and is set between major stars like Spica, Betelgeuse, Polaris, Canopus, and Alnitak. The 'core' of the Federation is 100 to 200 light years across, squeezed between multiple powers.
The Romulan border is 60 to 100 light years from Earth on average (which tracks with low warp era likely speeds and movements); the Klingon border is 90 to 120 light years away at the closest, beyond Regulus. Cardassians are between 100 to 200 light years from the Klingon border, which stretches itself at 200 to maybe even 500 light years tall (between Mu Leonis and Omega Fornacis) and the Tholians and Breen are respectively 'below' and 'above' the galactic plane in the further distance.
The Federation has been to Antares. It has been to Alnitak, Polaris, Mintaka, and nearly Sheliak. It has explored to Theta Pictoris (512 ly away) and maybe Avior. Few people live out there, though. Warp corridors do exist allowing substantially boosted speeds (like between Earth, Beta Rigel and Qo'nos, or from Ardana to Merak, or maybe down to Cestus and to Alpha Ceti) and these are well travelled, policed and guarded.
The Federation has also been to at least two 'Denebs' one of which may be Alpha Cygni. There is also two Rigels, and maybe two Antares, just possibly (Enterprise's pilot made the first of those a pretty much certainty) And some longer range trips can be feasible across 'grids' and quadrants (of one size or another) on occasion... with careful planning.
To me that fits 90 percent or so of the evidence. Newer shows may change that, but seem to be adopting the Mandel and Nemecek layouts going forward. After that, outliers may have to remain outliers.
As I'm not sure Roddenberry actually ever intended Federation ships, nor worlds, to routinely be thousands of light years apart. In the end though - each, as need be, to their own!